The present invention relates to a load distribution method for distributing a drive signal into each of a plurality of loads using a plurality of independent signal transmission lines on a printed circuit board. More particularly, the present invention relates to a load distribution system in which loads are divided into groups and a driving output pin is wired continuously to an input pin of each of the loads in every group with one stroke of each of a plurality of transmission lines in an order or sequence from the driving output pin, particularly when plural integrated circuits are mounted at predetermined positions on the printed circuit board and the wiring is effected for distributing the drive signal from the driving output pin to the plural input pins of loads in the integrated circuits.
When plural large scale integrated circuits (LSIs) are mounted and subjected to load drive wiring therebetween, the load drive wiring for an electronic device with the LSIs designed layerwise is effected in such a manner that loads are divided into some groups to provide independent signal transmission lines and a drive signal is supplied through the independent signal transmission lines. The advantage of this wiring resides in the fact that the signal transmission lines can be shortened, as disclosed, for example, in Japanese Laid-Open Patent Application (kokai) No. 58-213,448/1983. The method of grouping loads for the wiring in the manner as described hereinabove includes techniques of shortening distances of all the signal transmission lines to minimum lengths, minimizing the difference of capacities on each signal transmission lines by equalizing the number of loads, and the like.
However, the method of grouping the loads for the wiring in the manner described hereinabove merely considers individually a distance of the signal transmission lines, equalization of the number of loads, or the like. Accordingly, in a particular group of loads, a delay time may become too long or a load may not be driven due to an electric influence.